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Date: Fri, 12 May 2017 01:11:26 -0700
From: Christoph Hellwig <hch@infradead.org>
To: Arnd Bergmann <arnd@arndb.de>
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Subject: Re: [kernel-hardening] Re: [PATCH v9 1/4] syscalls: Verify address
 limit before returning to user-mode
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On Fri, May 12, 2017 at 09:43:40AM +0200, Arnd Bergmann wrote:
> How realistic and how useful would it be to first completely eliminate
> the ones that are in loadable modules and then wrapping the definition
> in #ifndef MODULE (or even make it an extern function)?

Should be fairly doable and might be a nice step towards cleaning the
mess up.  In fact with my seres a large part of those are gone, and
most of the remaining handler are ioctl handlers or what seems like
opencoded versions of probe_kernel_read.

But it won't help against exploits modifying addr_limit manually.